The objective of this work is to continue to describe in detail the structure-function biochemistry of homogenous neuraminidase derived from Arthrobacter sialophilus. The mechanism of action of this enzyme will be investigated with the use of conventional group-specific reagents and reporter groups. Site-directing irreversible inhibitors, and in particular, transition state affinity labels prepared from 2-deoxy-2,3-dehydro-N-acetylneuraminic acid methyl ester, will also be used to identify amino acid residues at the active site of the enzyme. These latter inhibitors may have potential chemotherapeutic value for the treatment of such infectious diseases as influenza and bacterial pneumonia. A radioimmunoassay for A. sialophilus neuraiminidase has been developed, which will be utilized to investigate the comparative biochemistry of neuraminidases and whether the active site of this enzyme is part of the antigenic site. A corollary objective is to continue our characterization and to explore application for immobilized neuraminidase. The potential applicability of the several types of immobilized enzyme, already prepared, in parallel with the homogenous unbound enzyme, for the clinical treatment of human acute myelocytic leukemia and other cancers will be carried out under collaborative arrangements.